Question

How do I find the cross product of `<-13, 4>` and `<-56, 0>`?

Answer 1

You have two options to evaluate the cross product:
1) the cross product of two vectors `vecv` and `vecw` is a vector with modulus equal to`|vecv|×|vecw|×sin(theta)` (`theta` is the angle between the vectors), direction perpendicular to the plane formed by the two vectors and oriented using the "thumb of the right hand" rule;
2) evaluate the determinant:
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()

In your case I would use the second option and use the first to check the result. So:

So basically, the result is a vector in the positive `z` direction and modulus 224, or:
`<0,0,224>`

Using the first approach you get the same result considering:

Try to evaluate the modulus (using `|vecv|×|vecw|×sin(theta)`) and consider the direction of the resulting vector you'll see that it matches.